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See detailThe Belgian election system
Bouhon, Frédéric ULg

Conference (2017, March 21)

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See detailTranscriptome analysis of pancreatic cells across distant species highlights novel important regulator genes.
tarifeno-Saldiva, estefania; Lavergne, Arnaud ULg; Bernard, Alice et al

in BMC Biology (2017), 15

Background Defining the transcriptome and the genetic pathways of pancreatic cells is of great interest for elucidating the molecular attributes of pancreas disorders such as diabetes and cancer. As the ... [more ▼]

Background Defining the transcriptome and the genetic pathways of pancreatic cells is of great interest for elucidating the molecular attributes of pancreas disorders such as diabetes and cancer. As the function of the different pancreatic cell types has been maintained during vertebrate evolution, the comparison of their transcriptomes across distant vertebrate species is a mean to pinpoint genes under strong evolutionary constrains due to their crucial function and which have preserved their selective expression in these pancreatic cell types. Results In this study, RNA-sequencing was performed on pancreatic alpha-, beta- and delta endocrine cells as well as the acinar and ductal exocrine cells isolated from adult zebrafish transgenic lines. Comparison of these transcriptomes identified many novel markers including transcription factors and signaling pathways components specific for each cell type. By performing interspecies comparisons, we identified hundreds of genes with conserved enriched expression in endocrine and exocrine cells among human, mouse and zebrafish. This list includes many genes known as crucial for pancreatic cell formation or function, but also pinpoints many factors whose pancreatic function is still unknown. A large set of endocrine-enriched genes can already be detected at early developmental stages as revealed by the transcriptomic profiling of embryonic endocrine cells, indicating a potential role in cell differentiation. The actual involvement of conserved endocrine genes in pancreatic cell differentiation was demonstrated in zebrafish for myt1b, whose invalidation leads to a reduction of alpha-cells, and for cdx4, selectively expressed in endocrine delta-cells and crucial for their specification. Intriguingly, comparison of the endocrine alpha- and beta-cell subtypes from human, mouse and zebrafish reveals a much lower conservation of the transcriptomic signatures for these two endocrine cell subtypes compared to the signatures of pan-endocrine and exocrine cells. These data suggest that the identity of the alpha- and beta-cells relies on a few key factors, corroborating numerous examples of inter-conversion between these two endocrine cell subtypes. Conclusion. This study highlights both evolutionary conserved and species-specific features that will help to unveil universal and fundamental regulatory pathways as well as pathways specific to human and laboratory animal models such as mouse and zebrafish. [less ▲]

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See detailUltimate strength of cylindrical shells with cutouts
Eui Lee, Sang; Sahin; Rigo, Philippe ULg et al

in Ships and Offshore Structures (2017)

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See detailSimultaneous synthesis and chemical functionalization of emulsion-templated porous polymers using nitroxide-terminated macromolecular surfactants
Mathieu, Kevin ULg; De Winter, Julien; Jérôme, Christine ULg et al

in Polymer Chemistry (2017), 8(11), 1850-1861

The design of functional 3D macroporous monoliths has become a necessity for a wide range of applications. Traditional post-modification strategies of porous materials are efficient but often consist in ... [more ▼]

The design of functional 3D macroporous monoliths has become a necessity for a wide range of applications. Traditional post-modification strategies of porous materials are efficient but often consist in tedious multi-steps processes. This work describes a straightforward macromolecular surfactant-assisted method for producing chemically functionalized macroporous polyHIPEs with interconnected structures. Accordingly, high internal phase emulsion-templated polymerizations were implemented in the presence of SG1-terminated amphiphilic copolymers prepared by nitroxide- mediated radical polymerization (NMP). The latter served as both stabilizers and functionalizing agents upon thermal activation of its terminal alkoxyamine and covalent anchoring of the released radical copolymer onto the walls of the scaffold. The effect of the polymerization temperature on the functionalization and openness of the final porous materials was explored. As a result, a range of open-cell styrene and acrylate-based polyHIPEs chemically grafted with PEO were obtained. Moreover, polyHIPEs were also decorated with alkyne-bearing PEO and subsequently modified via CuAAc click chemistry in order to demonstrate the potential of this macromolecular surfactants-assisted functionalization method. [less ▲]

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See detailL'extrême droite et le populisme en Europe
Debras, François ULg

Scientific conference (2017, March 21)

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See detailKNN-MDR: a learning approach for improving interactions mapping performances in genome wide association studies
Abo Al Chamlat, Sinan ULg; Farnir, Frédéric ULg

in BMC Bioinformatics (2017), 18

Background Finding epistatic interactions in large association studies like genome-wide association studies (GWAS) with the nowadays-available large volume of genomic data is a challenging and largely ... [more ▼]

Background Finding epistatic interactions in large association studies like genome-wide association studies (GWAS) with the nowadays-available large volume of genomic data is a challenging and largely unsolved issue. Few previous studies could handle genome-wide data due to the intractable difficulties met in searching a combinatorial explosive search space and statistically evaluating epistatic interactions given a limited number of samples. Our work is a contribution to this field. We propose a novel approach combining K-Nearest Neighbors (KNN) and Multi Dimensional Reduction (MDR) methods for detecting gene-gene interactions as a possible alternative to existing algorithms, e especially in situations where the number of involved determinants is high. After describing the approach, a comparison of our method (KNN-MDR) to a set of the other most performing methods (i.e., MDR, BOOST, BHIT, MegaSNPHunter and AntEpiSeeker) is carried on to detect interactions using simulated data as well as real genome-wide data. Results Experimental results on both simulated data and real genome-wide data show that KNN-MDR has interesting properties in terms of accuracy and power, and that, in many cases, it significantly outperforms its recent competitors. Conclusions The presented methodology (KNN-MDR) is valuable in the context of loci and interactions mapping and can be seen as an interesting addition to the arsenal used in complex traits analyses. [less ▲]

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See detailOils and CO2, a promising combination for designing insulating foams and high performance coatings
Detrembleur, Christophe ULg; Alves, Margot ULg; Grignard, Bruno ULg et al

Conference (2017, March 21)

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic ... [more ▼]

Making plastics more sustainable by valorizing waste CO2 as a cheap, inexhaustible and renewable feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprint materials and technologies. With a global production estimated to 18 million tons for 2016, polyurethane (PU) is one of the most important polymers in our everyday life applications (automotive, building and construction, coatings, etc.). Industrially, PU is produced by step-growth polymerization between di- or polyisocyanates and di- or polyols. However, isocyanates are toxic and drastic changes in the REACH regulations limiting/banning the use of isocyanates are expected. There is a need today to develop new greener and safer alternatives to produce PU. Valorizing CO2 as C1 feedstock for producing precursors entering in the synthesis of polyurethanes by a non-isocyanate route (NIPU) is a promising strategy to solve this challenge. In this talk, we will focus on the synthesis and characterization of novel NIPUs foams for thermal insulation, and NIPUs coatings for metal protection. Our research highlights benefit of merging bio-resources (such as vegetable oils) with carbon dioxide transformation. In the first part of this talk, we will report on the fast synthesis of bio- and CO2-sourced cyclic carbonates by coupling CO2 with epoxides using a new highly efficient bicomponent homogeneous organocatalyst under solvent-free and mild experimental conditions. The mechanism of the activation of the reaction will be discussed, and scaling up of the technology will be demonstrated (15kg scale). In the second part, we will illustrate the use of these bio- and CO2-sourced cyclic carbonates for the production of microcellular NIPU foams with closed cells morphology for thermal insulating applications, but also for preparing hybrid NIPUs coatings for metal protection. [less ▲]

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See detailInfluence of granular fraction and origin of recycled concrete aggregates on their properties
Zhao, Zengfeng ULg; Courard, Luc ULg; Michel, Frédéric ULg et al

in European Journal of Environmental and Civil Engineering (2017)

Large quantities of construction and demolition wastes are produced each year. In order to make good use of recycled concrete aggregates (RCA) in concrete, it is very important to study the influence of ... [more ▼]

Large quantities of construction and demolition wastes are produced each year. In order to make good use of recycled concrete aggregates (RCA) in concrete, it is very important to study the influence of the granular fraction and the origin of RCA on their properties. In this study, RCA from industrial produced blocks (RCA_Blocks) and slabs (RCA_Slabs) were crushed and then separated into four granular fractions (0/2, 2/6.3, 6.3/14, 14/20 mm). Each granular fraction of RCA was physically characterised. Real RCA from recycling plant were also used for comparison. The results showed that recycled sands offered significantly higher cement paste content (higher bound water content) than coarse recycled aggregates. The fine RCA had therefore a higher water absorption coefficient compared to coarser fractions of RCA. The water absorption of finer fraction of RCA could be extrapolated precisely from the relationship between water absorption and cement paste content (or bound water content) of three coarse fractions of RCA. The values of hardened cement paste content obtained for the RCA_Blocks were lower than those measured on the RCA_Slabs, which was due to a smaller amount of initial cement paste content in blocks. The results showed that RCA_Slabs were more angular than RCA_Blocks. [less ▲]

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See detailConférence-débat avec le Raoul Collectif
Cormann, Grégory ULg; Hamers, Jérémy ULg

Conference given outside the academic context (2017)

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See detailSynergistic observations of the giant planets with HST and JWST: Jupiter's auroral emissions
Grodent, Denis ULg

Conference (2017, March 20)

The James Webb Space Telescope is perfectly suited to observe most Solar System objects, including the extended giant planets. Its high sensitivity, high spatial resolution, field of view, very high ... [more ▼]

The James Webb Space Telescope is perfectly suited to observe most Solar System objects, including the extended giant planets. Its high sensitivity, high spatial resolution, field of view, very high spectral resolution and wide spectral coverage all combine to make JWST a fantastic instrument that will result in significant advances and progress in most fields of Solar System exploration. Here, we focus on the case of Jupiter’s aurora for several reasons. 1) The auroral emissions on Jupiter are very intense, both in ultraviolet and in infrared. Each of these bandpasses is bringing complementary information on how Jupiter is interacting with its near and distant environment. 2) Even though Jupiter’s aurora appears to be responding to the conditions prevailing in the solar wind, contrary to the Earth it is a permanent emission that can also be observed on the sunlit side of the planet. 3) The NASA Juno mission is currently exploring the magnetosphere and the atmosphere of this planet with a suite of in situ and remote instruments, including an ultraviolet spectrograph (UVS) and an infrared imaging spectrograph (JIRAM). The Juno mission is gathering a broad scientific community that will foster the study of Jupiter’s system for several years. 4) A large HST program was allocated in support of the NASA Juno prime mission (GO-14634) and is currently providing us with regular movies of Jupiter’s ultraviolet aurora. They provide a global magnetospheric context for the different Juno instruments, as well as for the numerous ground based (infrared) and space based observatories participating to the Juno mission. 5) It is currently very difficult to plan truly simultaneous UV and IR observations, mainly because of the inherent limitations of Earth based infrared telescopes. As a result, comparisons of Jupiter’s auroral emissions rest on a very limited dataset. Nevertheless, they are suggesting similarities and discrepancies between IR and UV aurorae, the study of which would greatly benefit from synergistic observations with HST and JWST. 6) The case of Saturn’s aurora is as important, especially in view of the upcoming ‘Grand Finale’ of the Cassini mission, and all above arguments apply to Saturn as well. The case of Uranus and Neptune’s aurorae still belongs to the area of discovery and will take full advantage of JWST’s advanced capabilities. [less ▲]

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See detailCatalytic functionalisation of starch and amylose using plant oils: towards polymeric materials and composites
Scholten, Philip ULg; Söyler, Zafer; Detrembleur, Christophe ULg et al

Poster (2017, March 19)

Fossil fuels have been the main source of starting materials for the chemical industry over the last century. Especially synthetic polymers rely on this feedstock and are indispensible for mankind’s ... [more ▼]

Fossil fuels have been the main source of starting materials for the chemical industry over the last century. Especially synthetic polymers rely on this feedstock and are indispensible for mankind’s technological advances and status quo. However, a shift to renewable and sustainable resources is needed, as the end of the fossil fuel era is in sight. Biomass presents one possible alternative to fossil fuels, as it consists of a large pool of different chemicals and is inexhaustible. Cellulose, and the closely related starch and amylose, are available cheaply from plants and have favourable properties, such as high strength, thermal stability and biodegradability. However, such poly(saccharides) have been difficult to use directly as materials because of the lack of thermoplasticity, low solubility and high hydrophilicity. Modifications are thus necessary to be able to exploit their advantageous properties. Recently, our group published the catalytic transesterification of maize starch with different plant oils to obtain fully renewable fatty acid starch esters in a sustainable fashion. Polymeric materials with glass transition temperatures (Tgs), soluble in common organic solvents and an increased hydrophobicity were obtained. Compatibilisation tests of the modified starch and amylose with low-density poly(ethylene) (LDPE) and cellulose are being investigated to obtain composites of commodity plastics with improved mechanical properties. [less ▲]

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See detailLichtenstein procedure under local anaesthesia
DETRY, Olivier ULg

Conference (2017, March 18)

LICHTENSTEIN REPAIR UNDER LOCAL ANAESTHESIA Pr Olivier Detry, Dpt of Abdominal Surgery and Transplantation, CHU Liège, Liège, Belgium. Email: oli.detry@chu.ulg.ac.be Despite many studies confirming the ... [more ▼]

LICHTENSTEIN REPAIR UNDER LOCAL ANAESTHESIA Pr Olivier Detry, Dpt of Abdominal Surgery and Transplantation, CHU Liège, Liège, Belgium. Email: oli.detry@chu.ulg.ac.be Despite many studies confirming the feasibility and the interest of local anaesthesia for inguinal hernia repair [1-3], its use is not generalized amongst abdominal surgeons. The advantages of local anaesthesia are indeed clear, including reduced costs, reduced hospital stay and reduced post operative pain. The success of the procedure depends on the skills and the motivation of the surgeon, of the nursing teams, and of the patient him/herself. Perfect knowledge of the surgical technique and of the regional nerve anatomy is required. The Lichtenstein repair may be easily performed under local anaesthesia, but should be proposed in the early experience to non-obese patients suffering from limited inguinal hernia. It can even be performed by surgical residents [4]. Practically, local anaesthesia requires some patience and quiet in the operative room. Operators should be aware that the action of local anaesthesia is delayed after injection. Local anaesthetics should be buffered [5] and at body temperature at time of injection. Local anaesthetics containing Adrenalin allow longer pain control, with limitation of bleeding and less toxicity. Large and brutal movements should be avoided. Transversus abdominis plane (TAP) block can also be proposed [6]. The surgical and anaesthetic techniques for inguinal hernia repair should be tailored to the specific characteristics of the hernia and of the patient. There is no method of choice that might fit for every patient. References [1] van Veen RN, Mahabier C, Dawson I, Hop WC, Kok NF, Lange JF, et al. Spinal or local anesthesia in lichtenstein hernia repair: a randomized controlled trial. Ann Surg 2008;247:428-433. [2] Verstraete L, Becaus N, Swannet H, Ceelen W, Duchateau L, Speybroeck N. Long term outcome after lichtenstein hernia repair using general, locoregional or local anaesthesia. Acta Chir Belg 2015;115:136-141. [3] Dhankhar DS, Sharma N, Mishra T, Kaur N, Singh S, Gupta S. Totally extraperitoneal repair under general anesthesia versus Lichtenstein repair under local anesthesia for unilateral inguinal hernia: a prospective randomized controlled trial. Surg Endosc 2014;28:996-1002. [4] Paajanen H, Varjo R. Ten-year audit of Lichtenstein hernioplasty under local anaesthesia performed by surgical residents. BMC Surg 2010;10:24. [5] Ball EL, Sanjay P, Woodward A. Comparison of buffered and unbuffered local anaesthesia for inguinal hernia repair: a prospective study. Hernia : the journal of hernias and abdominal wall surgery 2006;10:175-178. [6] Milone M, Di Minno MN, Musella M, Maietta P, Salvatore G, Iacovazzo C, et al. Outpatient inguinal hernia repair under local anaesthesia: feasibility and efficacy of ultrasound-guided transversus abdominis plane block. Hernia : the journal of hernias and abdominal wall surgery 2013;17:749-755. [less ▲]

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See detailRNAi inhibition of feruloyl CoA 6'-hydroxylase reduces scopoletin biosynthesis and post-harvest physiological deterioration in cassava (Manihot esculenta Crantz) storage roots.
Liu, Shi; Zainuddin, Ima M.; Vanderschuren, Hervé ULg et al

in Plant Molecular Biology (2017)

Cassava (Manihot esculenta Crantz) is a major world crop, whose storage roots provide food for over 800 million throughout the humid tropics. Despite many advantages as a crop, the development of cassava ... [more ▼]

Cassava (Manihot esculenta Crantz) is a major world crop, whose storage roots provide food for over 800 million throughout the humid tropics. Despite many advantages as a crop, the development of cassava is seriously constrained by the rapid post-harvest physiological deterioration (PPD) of its roots that occurs within 24-72 h of harvest, rendering the roots unpalatable and unmarketable. PPD limits cassava's marketing possibilities in countries that are undergoing increased development and urbanisation due to growing distances between farms and consumers. The inevitable wounding of the roots caused by harvesting triggers an oxidative burst that spreads throughout the cassava root, together with the accumulation of secondary metabolites including phenolic compounds, of which the coumarin scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one) is the most abundant. Scopoletin oxidation yields a blue-black colour, which suggests its involvement in the discoloration observed during PPD. Feruloyl CoA 6'-hydroxylase is a controlling enzyme in the biosynthesis of scopoletin. The cassava genome contains a seven membered family of feruloyl CoA 6'-hydroxylase genes, four of which are expressed in the storage root and, of these, three were capable of functionally complementing Arabidopsis T-DNA insertion mutants in this gene. A RNA interference construct, designed to a highly conserved region of these genes, was used to transform cassava, where it significantly reduced feruloyl CoA 6'-hydroxylase gene expression, scopoletin accumulation and PPD symptom development. Collectively, our results provide evidence that scopoletin plays a major functional role in the development of PPD symptoms, rather than merely paralleling symptom development in the cassava storage root. [less ▲]

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